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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /drivers/mmc/core/pwrseq_emmc.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/mmc/core/pwrseq_emmc.c')
-rw-r--r-- | drivers/mmc/core/pwrseq_emmc.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/drivers/mmc/core/pwrseq_emmc.c b/drivers/mmc/core/pwrseq_emmc.c new file mode 100644 index 000000000..154f4204d --- /dev/null +++ b/drivers/mmc/core/pwrseq_emmc.c @@ -0,0 +1,121 @@ +/* + * Copyright (C) 2015, Samsung Electronics Co., Ltd. + * + * Author: Marek Szyprowski <m.szyprowski@samsung.com> + * + * License terms: GNU General Public License (GPL) version 2 + * + * Simple eMMC hardware reset provider + */ +#include <linux/delay.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/reboot.h> + +#include <linux/mmc/host.h> + +#include "pwrseq.h" + +struct mmc_pwrseq_emmc { + struct mmc_pwrseq pwrseq; + struct notifier_block reset_nb; + struct gpio_desc *reset_gpio; +}; + +#define to_pwrseq_emmc(p) container_of(p, struct mmc_pwrseq_emmc, pwrseq) + +static void mmc_pwrseq_emmc_reset(struct mmc_host *host) +{ + struct mmc_pwrseq_emmc *pwrseq = to_pwrseq_emmc(host->pwrseq); + + gpiod_set_value_cansleep(pwrseq->reset_gpio, 1); + udelay(1); + gpiod_set_value_cansleep(pwrseq->reset_gpio, 0); + udelay(200); +} + +static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + struct mmc_pwrseq_emmc *pwrseq = container_of(this, + struct mmc_pwrseq_emmc, reset_nb); + gpiod_set_value(pwrseq->reset_gpio, 1); + udelay(1); + gpiod_set_value(pwrseq->reset_gpio, 0); + udelay(200); + + return NOTIFY_DONE; +} + +static const struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = { + .reset = mmc_pwrseq_emmc_reset, +}; + +static int mmc_pwrseq_emmc_probe(struct platform_device *pdev) +{ + struct mmc_pwrseq_emmc *pwrseq; + struct device *dev = &pdev->dev; + + pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL); + if (!pwrseq) + return -ENOMEM; + + pwrseq->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW); + if (IS_ERR(pwrseq->reset_gpio)) + return PTR_ERR(pwrseq->reset_gpio); + + if (!gpiod_cansleep(pwrseq->reset_gpio)) { + /* + * register reset handler to ensure emmc reset also from + * emergency_reboot(), priority 255 is the highest priority + * so it will be executed before any system reboot handler. + */ + pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb; + pwrseq->reset_nb.priority = 255; + register_restart_handler(&pwrseq->reset_nb); + } else { + dev_notice(dev, "EMMC reset pin tied to a sleepy GPIO driver; reset on emergency-reboot disabled\n"); + } + + pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops; + pwrseq->pwrseq.dev = dev; + pwrseq->pwrseq.owner = THIS_MODULE; + platform_set_drvdata(pdev, pwrseq); + + return mmc_pwrseq_register(&pwrseq->pwrseq); +} + +static int mmc_pwrseq_emmc_remove(struct platform_device *pdev) +{ + struct mmc_pwrseq_emmc *pwrseq = platform_get_drvdata(pdev); + + unregister_restart_handler(&pwrseq->reset_nb); + mmc_pwrseq_unregister(&pwrseq->pwrseq); + + return 0; +} + +static const struct of_device_id mmc_pwrseq_emmc_of_match[] = { + { .compatible = "mmc-pwrseq-emmc",}, + {/* sentinel */}, +}; + +MODULE_DEVICE_TABLE(of, mmc_pwrseq_emmc_of_match); + +static struct platform_driver mmc_pwrseq_emmc_driver = { + .probe = mmc_pwrseq_emmc_probe, + .remove = mmc_pwrseq_emmc_remove, + .driver = { + .name = "pwrseq_emmc", + .of_match_table = mmc_pwrseq_emmc_of_match, + }, +}; + +module_platform_driver(mmc_pwrseq_emmc_driver); +MODULE_LICENSE("GPL v2"); |